George Pell's final legal avenue to appeal sexual abuse convictions

George Pell is almost certain to take his fight against his child sex convictions to the High Court, a leading barrister says.

But it would be unusual for Australia's highest judicial body to agree to reconsider all the evidence heard by the jury that convicted the Catholic cardinal, leading Melbourne lawyer David Galbally, QC, said.

The High Court is Pell's final avenue of appeal after Victoria's Court of Appeal yesterday upheld his December conviction for the rape of a 13-year-old choirboy and sexual assault of another at St Patrick's Cathedral in Melbourne in 1996.

Pell spent last night back behind bars where he will remain for six years if he serves his full term.

The likelihood Pell will seek leave from the High Court to appeal yesterday's ruling is bolstered by a 2-1 split between Chief Justice Anne Ferguson and President Chris Maxwell and dissenting Justice Mark Weinberg.

Justice Weinberg said in his dissenting ruling he believed there was significant possibility Pell did not commit the crimes he was convicted of.

Mr Galbally QC said decisions on a further appeal would depend on whether there are questions of law for the High Court to determine.

Mr Galbally said the High Court decision would be carefully deliberated as it will have an impact on future cases, although he expects matters to move quickly.

"This case has attracted enormous publicity and I think it is in the interests of justice that it be dealt with very quickly," he said.

The Vatican said it will let Pell exhaust all legal avenues of appeal before examining his case in its own canon law investigation – an action consistent with the Vatican's handling of other sex abuse cases.

"As the proceedings continue to develop, the Holy See recalls that the Cardinal has always maintained his innocence throughout the judicial process and it is his right to appeal to the High court," Vatican spokesman Matteo Bruni said in a statement.

"Now, together with the Church in Australia, the Holy See confirms its closeness to the victims of sexual abuse and its commitment to pursue, through the competent ecclesiastical authorities, those members of clergy who commit such abuse."

Pope Francis did not explicitly comment on the case, although he delivered a cryptic tweet overnight.

"It takes more strength to repair than to build, to start anew than to begin, to be reconciled than to get along. This is the strength that God gives us," the Pope tweeted.

George Pell was an adviser to Pope Francis and a member of the Vatican's inner-sanctum.

The family of Pell's deceased victim have said they're likely to sue the church or Pell individually for damages, although Mr Galbally believes the case could be difficult.

"They would need to be able to show - if they are going to bring the Catholic church in - that [Pell] was acting within the authority of the Catholic Church," he said.

"It will be a very interesting case and one that will attract a lot of attention."